The objective of this POC study are firstly to evaluate and compare the efficacy and safety of escalating doses of BF2.649 and BF2.649 add on Modafinil (200 mg/day) on cataplexy attacks, and secondly to evaluate the additive/synergistic effect and safety of the combination of BF2.649 and Modafinil on EDS as assessed by both of objective and subjective measures including ESS, MWT, patients sleep diary.